TSLPersistentCacheData Class Reference

Detailed Description

Persistent cache class.

Holds settings used to initialise the persistent cache of a TSLMapDataLayer.

Use the 'loadFromIniFile' method to load settings from an existing persistent cache ini file.

Public Member Functions
	TSLPersistentCacheData ()
bool	checkValidityDuringIdle () const
void	checkValidityDuringIdle (bool newVal)
void	destroy ()
const char *	directory () const
void	directory (const char *newVal)
bool	flushDuringIdle () const
void	flushDuringIdle (bool newVal)
int	garbagePercentage () const
void	garbagePercentage (int newVal)
bool	indexEveryUpdate () const
void	indexEveryUpdate (bool newVal)
bool	loadFromIniFile (const char *fileName, const char *section)
bool	maxCompression () const
void	maxCompression (bool newVal)
int	maxSizeMB () const
void	maxSizeMB (int newVal)
const char *	sortOrder () const
void	sortOrder (const char *newVal)
TSLTMC	tmcUnit () const
void	tmcUnit (TSLTMC newVal)
void *	operator new (size_t size) TSL_NO_THROW
void *	operator new (size_t size, char *filename, int line)

Constructor & Destructor Documentation

TSLPersistentCacheData()

TSLPersistentCacheData::TSLPersistentCacheData

(

)

Member Function Documentation

checkValidityDuringIdle() [1/2]

bool TSLPersistentCacheData::checkValidityDuringIdle

(

)

const

Returns the checkValidityDuringIdle flag.

If this flag is true, then during idle processing, tiles that are in the cache but have not been used this session are checked for validity in case they are needed.

checkValidityDuringIdle() [2/2]

void TSLPersistentCacheData::checkValidityDuringIdle

(

bool

newVal

)

Sets the checkValidityDuringIdle flag.

If this flag is true, then during idle processing, tiles that are in the cache but have not been used this session are checked for validity in case they are needed.

Parameters

newVal

value required for the checkValidityDuringIdle flag

destroy()

void TSLPersistentCacheData::destroy

(

)

Destroy method. This should be called rather than deleting the persistent cache object, since the calls are redirected internally to MapLink.

directory() [1/2]

const char * TSLPersistentCacheData::directory

(

)

const

Returns the directory where the persistent tiles should be stored. Any environment variables specified in this path are expanded.

directory() [2/2]

void TSLPersistentCacheData::directory

(

const char *

newVal

)

Sets the directory where the persistent tiles should be stored. Any environment variables specified in this path are expanded.

Parameters

newVal

value for the directory

flushDuringIdle() [1/2]

bool TSLPersistentCacheData::flushDuringIdle

(

)

const

Returns the flush during idle flag.

If this flag is true, then the persistent cache is flushed during idle processing.

flushDuringIdle() [2/2]

void TSLPersistentCacheData::flushDuringIdle

(

bool

newVal

)

Sets the flush during idle flag.

If this flag is true, then the persistent cache is flushed during idle processing.

Parameters

newVal

value required for the flushDuringIdle flag.

garbagePercentage() [1/2]

int TSLPersistentCacheData::garbagePercentage

(

)

const

Returns the percentage of the cache that is freed during a flush.

For example, if this value was 10, then the cache would be reduced to 90% of its maximum size when flushed. The tiles would be deleted based upon the priority sort order.

garbagePercentage() [2/2]

void TSLPersistentCacheData::garbagePercentage

(

int

newVal

)

Sets the percentage of the cache that is freed during a flush.

For example, if this value was 10, then the cache would be reduced to 90% of its maximum size when flushed. The tiles would be deleted based upon the priority sortOrder specified above.

Parameters

newVal

the value required

indexEveryUpdate() [1/2]

bool TSLPersistentCacheData::indexEveryUpdate

(

)

const

Returns the indexEveryUpdate flag.

This flag indicates whether the cache index should be written whenever it needs updating. This will affect performance when the cache is large, or the file system slow, but may be necessary if the system cannot be closed cleanly. The index is usually written when the TSLMapDataLayer is deleted.

indexEveryUpdate() [2/2]

void TSLPersistentCacheData::indexEveryUpdate

(

bool

newVal

)

Sets the indexEveryUpdate flag.

This flag indicates whether the cache index should be written whenever it needs updating. This will affect performance when the cache is large, or the file system slow, but may be necessary if the system cannot be closed cleanly. The index is usually written when the TSLMapDataLayer is deleted.

Parameters

newVal

required value for the indexEveryUpdate flag

loadFromIniFile()

bool TSLPersistentCacheData::loadFromIniFile	(	const char *	fileName,
		const char *	section )

Loads the persistent cache settings from an existing persistent cache ini file.

The configuration file should be of the form:

[persistent cache]
 
directory=%DASCACHEPATH%/pcache
maxSizeMb=20
sortOrder=VACS
maxCompression=1
tmcUnit=10
flushDuringIdle=0
checkValidityDuringIdle=0
garbagePercentage=10
indexEveryUpdate=0

The entries in the configuration file are:

• directory: This is the directory where the persistent tiles should be stored. Any environment variables specified in this path are expanded.
• maxSizeMb: This is the maximum size of the persistent cache, in Mb.
• sortOrder: This string defines the priority order for sort tiles. When flushing the cache, tiles of a lower priority will be flushed first. Each letter in the string represents a boolean condition used when sorting. 'V' is whether the tile has been validated or not. 'A' is the last access time - more recent is a higher priority. 'C' is the number of times the tile has been accessed whilst in the cache. 'S' is the size of the tile - larger is considered more important to cache. The order of these letters in the string indicates the relative priority of these conditions. The example 'VACS' sorts first by tile validity, then by last access time, then by access count and finally by tile size.
• maxCompression: If this flag is 1, then the tiles are stored in the cache as if the 'optimise for size' flag was set in the processing tool. Note that this only has an effect if the tile was optimised when created, although this can be applied if optimised for speed.
• tmcUnit: This value is used when the maxCompression flag is 1. It represents the 'Optimisation scale factor' which would be entered in the MapLink Processing tool.
• flushDuringIdle: If this flag is 1, then the persistent cache is flushed during idle processing.
• checkValidityDuringIdle: If this flag is 1, then during idle processing, tiles that are in the cache but have not been used this session are checked for validity in case they are needed.
• garbagePercentage: This is the percentage of the cache that is freed during a flush. For example, if this value was 10, then the cache would be reduced to 90% of its maximum size when flushed. The tiles would be deleted based upon the priority sortOrder specified above.
• indexEveryUpdate: This flag indicates whether the cache index should be written whenever it needs updating. This will affect performance when the cache is large, or the file system slow, but may be necessary if the system cannot be closed cleanly. The index is usually written when the TSLMapDataLayer is deleted.

Parameters

fileName	This is the name of configuration file. The file must be local, not remote. The filename may be absolute, or the file may be found in the system path or maplink path search directories.
section	This is the section within the configuration file. In the example above, this is "persistent cache".

maxCompression() [1/2]

bool TSLPersistentCacheData::maxCompression

(

)

const

Returns the maxCompression flag.

If this flag is true, then the tiles are stored in the cache as if the 'optimise for size' flag was set in the processing tool. Note that this only has an effect if the tile was optimised when created, although this can be applied if optimised for speed.

maxCompression() [2/2]

void TSLPersistentCacheData::maxCompression

(

bool

newVal

)

Sets the maxCompression flag.

If this flag is true, then the tiles are stored in the cache as if the 'optimise for size' flag was set in the processing tool. Note that this only has an effect if the tile was optimised when created, although this can be applied if optimised for speed.

Parameters

newVal

value required for the maxCompression flag

maxSizeMB() [1/2]

int TSLPersistentCacheData::maxSizeMB

(

)

const

Returns the maximum size of the persistent cache, in MB.

maxSizeMB() [2/2]

void TSLPersistentCacheData::maxSizeMB

(

int

newVal

)

Sets the maximum size of the persistent cache, in MB.

Parameters

newVal

required size in MB.

operator new() [1/2]

void * TSLPersistentCacheData::operator new

(

size_t

size

)

Allocation override for API redirection

operator new() [2/2]

void * TSLPersistentCacheData::operator new	(	size_t	size,
		char *	filename,
		int	line )

When included in an MFC application in debug mode, the debug new expects this to be here. Override it and return the same as the normal one. The library must include it when compiled in release mode, since the user's application may be in debug mode.

sortOrder() [1/2]

const char * TSLPersistentCacheData::sortOrder

(

)

const

Returns the string defining the priority order for sorting tiles.

When flushing the cache, tiles of a lower priority will be flushed first. Each letter in the string represents a boolean condition used when sorting. 'V' is whether the tile has been validated or not. 'A' is the last access time - more recent is a higher priority. 'C' is the number of times the tile has been accessed whilst in the cache. 'S' is the size of the tile - larger is considered more important to cache. The order of these letters in the string indicates the relative priority of these conditions. The example 'VACS' sorts first by tile validity, then by last access time, then by access count and finally by tile size.

sortOrder() [2/2]

void TSLPersistentCacheData::sortOrder

(

const char *

newVal

)

Sets the string defining the priority order for sort tiles.

When flushing the cache, tiles of a lower priority will be flushed first. Each letter in the string represents a boolean condition used when sorting. 'V' is whether the tile has been validated or not. 'A' is the last access time - more recent is a higher priority. 'C' is the number of times the tile has been accessed whilst in the cache. 'S' is the size of the tile - larger is considered more important to cache. The order of these letters in the string indicates the relative priority of these conditions. The example 'VACS' sorts first by tile validity, then by last access time, then by access count and finally by tile size.

Parameters

newVal

the required priority order.

tmcUnit() [1/2]

TSLTMC TSLPersistentCacheData::tmcUnit

(

)

const

Returns the optimisation scale factor.

This value is used when the maxCompression flag is true. It represents the 'Optimisation scale factor' which would be entered in the MapLink Processing tool.

tmcUnit() [2/2]

void TSLPersistentCacheData::tmcUnit

(

TSLTMC

newVal

)

Sets the optimisation scale factor.

Parameters

newVal

new scale factor.

This value is used when the maxCompression flag is true. It represents the 'Optimisation scale factor' which would be entered in the MapLink Processing tool.